Seasonal and diurnal variability of pressure fluctuation in the infrasound frequency range observed in the Czech microbarograph network

Infrasound environments in the Czech microbarograph network were studied. Reference Fourier amplitude spectra were calculated from data measured at three microbarograph sites of the network in May 2011-April 2012; directional analysis of infrasound arrivals in the frequency band 0.15-0.4 Hz was performed for the microbarograph array at Panská Ves in May 2014-April 2015. Diurnal, seasonal and site-to-site variability of the reference spectra was evaluated. Site-to-site variability is influenced by the location of the respective sensors in the open air and inside the observatory buildings and by local noise phenomena like wind turbines. Diurnal variability is well developed in summer with maximum ambient noise levels during the daytime and minima at night. Seasonal variability is observed at night with maxima in winter and minima in summer. Wind and wind eddies seem to be an important source of ambient noise in measurements in the Czech microbarograph network. A distinct spectral peak occurs near 0.2 Hz with amplitudes by about one order of magnitude higher in winter than in summer. Its seasonal variability is related to seasonal propagation of microbaroms from the source region in the Northern Atlantic.     

Non-linear dependence and teleconnections in climate data: sources,relevance, nonstationarity

Quantification of relations between measured variables of interest by statistical measures of dependence is a common step in analysis of climate data. The choice of dependence measure is key for the results of the subsequent analysis and interpretation. The use of linear Pearson’s correlation coefficient is widespread and convenient. On the other side, as the climate is widely acknowledged to be a nonlinear system, nonlinear dependence quantification methods, such as those based on information-theoretical concepts, are increasingly used for this purpose. In this paper we outline an approach that enables well informed choice of dependence measure for a given type of data, improving the subsequent interpretation of the results. The presented multi-step approach includes statistical testing, quantification of the specific non-linear contribution to the interaction information, localization of areas with strongest nonlinear contribution and assessment of the role of specific temporal patterns, including signal nonstationarities. In detail we study the consequences of the choice of a general nonlinear dependence measure, namely mutual information, focusing on its relevance and potential alterations in the discovered dependence structure. We document the method by applying it to monthly mean temperature data from the NCEP/NCAR reanalysis dataset as well as the ERA dataset. We have been able to identify main sources of observed non-linearity in inter-node couplings. Detailed analysis suggested an important role of several sources of nonstationarity within the climate data. The quantitative role of genuine nonlinear coupling at monthly scale has proven to be almost negligible, providing quantitative support for the use of linear methods for monthly temperature data.     

Phenological observations made by the I. R. Bohemian Patriotic�CEconomic Society, 1828�C1847

Drought forecasting is a critical component of drought risk management. Identification of effective predictors is a major component of forecasting models. Sea surface temperature (SST) and sea level pressure (SLP) are relevant predictors for short- to long-term drought forecasts. However, these datasets are captured globally within a cell-wise network. This paper describes an approach to locate the most effective cells of the SST and SLP datasets using data mining. They are then applied as input to an adaptive neurofuzzy inference system (ANFIS) model to forecast possible droughts 3, 6, and 9?months in advance. Tehran plain was selected as the study area, and drought events are designated using the effective drought index (EDI). In another treatment, past values of the EDI time series were introduced to the ANFIS and the results compared with the previous findings. It was shown that R ² values were higher for all cases applying the SST/SLP datasets. Additionally, the performance of SST/SLP datasets and the ANFIS model was assessed according to ??drought?? or ??wet?? classification, and it was concluded that more than 90% of the time the ANFIS model detected the drought status correctly or with only a one class error.     

Terrane character of the north-east margin of the Moldanubian Zone: the Kutná Hora Crystalline Complex,Bohemian Massif

Three major allochthonous units have been distinguished on the north-eastern border of the Moldanubian Zone, which differ each from other in lithology and structural and metamorphic evolution. Their present day position displays significant metamorphic and structural inversion resulting from progressive nappe stacking during the Variscan orogeny. The uppermost-Gföhl Unit consists of anatectic rocks containing high temperature/high pressure relics, i.e. granulites, eclogites and garnet peridotites. The rocks of the Gföhl Unit were strongly mylonized during uplift and later also extensively migmatized in the kyanite stability field. The Kouiim Nappe is built up by a sequence of fine-grained leucocratic migmatites with preserved relics of a pre-Variscan deformation event. This event was terminated by the intrusion of coarse-grained porphyritic granites, converted into augen orthogneisses by the Variscan orogeny. The lowermost Micaschist Zone was formed from a sequence of metapelites intercalated with diopsidic amphibolites.During uplift from deep crustal zones the Gföhl Unit cut off a thick slice of the basement crustal material represented by the Kourim Nappe. The quartzo-feldspathic material of the Kourim Nappe acted as a major shear interface because of its extreme ductility under the conditions found in the middle crust. This process occurred under amphibolite facies metamorphism. The continuous uplift of the nappe pile induced another crustal segment in the nappe stack, represented by the Micaschist Zone. The whole nappe sequence was then thrust over the Moldanubian Zone. A westward sense of shear is suggested for the whole uplift history. The kinematic pattern was complicated by later strike-slip ductile faults which finished the recent geological configuration.Correspondence to: J. Synek     

Heat flow in the upper-silesian coal basin: Re-evaluation of data with special attention to the lithology

Summary The area of the Upper Silesian Coal Basin was characterized by generally high heat flow ranging from 60 to 120 mWm^–2, mean 82±16 mWm^–2, which has been difficult to explain. Therefore all published data on the heat flow in this region (n=37) were summarized and re-evaluated. Special attention was paid to the detailed assessment of the lithological structure and the contribution of the individual rock types to the characteristic in-situ thermal conductivity. Also the thermal conductivity of the coal bearing layers was estimated and its effect on the temperature-depth distribution was investigated. The application of the data obtained for the representative thermal conductivity profiles of the whole drilled section considerably reduced the mean heat flow to 70±8 mWm^–2. The latter value is fully compatible with the tectonic structure of the northern part of the Carpathian Frontal Foredeep. Slightly increased geothermal activity compared with the heat flow field of the adjacent part of the Bohemian Massif corresponds to certain deep geological rejuvenation during the creation of the Western Carpathians.

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a -uu aa aamum nu uuau mn nma (m 60 ¶rt; 120 m.^–2 nu ¶rt; 82±16 m. ^–2), m ¶rt;a ¶rt u. m u u nm a nua ¶rt;a mn nma (n=37) ¶rt; ¶rt;a ua. ua ¶rt; ¶rt;ma aau umuu aa u u mnn¶rt;mu in situ ¶rt; a¶rt; muna n¶rt;. a a mnn¶rt;m m, a ma, a ma u¶rt;aa an¶rt;u mnam nu. nau n mam ¶rt; nuau mnn¶rt;mu m u amu aa nu am uum ¶rt;u mn nm ¶rt; 70±8 m.^–2. a uua n mam mmu u amu anam a nua. m uumu amumu n au mn n nuaa amu aua mmmmuuau amuuauu nu uauu um ana¶rdt; anam.

     

Interpretation of spectra of geomagnetic pulsations as a spectrum of modulated oscillations

Summary The analysis of spectra of modulated oscillations is used to show how these oscillations are distorted when recorded by an instrument whose characteristics depend on frequency, and under what conditions the parameters of the original modulated oscillations can be derived directly from the record. Geomagnetic Pc3 and Pi2 pulsations, recorded at the Budkov Observatory, are discussed; these can be interpreted as amplitude or frequency modulated oscillations.

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a aaua nm ¶rt;ua uu naa, a mu uuu ua nu umauu nu, aamumuu m aum m amm, u nu au u n u anuu mu naam naa ¶rt;ua uu. aa maaum nauu Pc3 u Pi2 amuu ¶rt;, m m m umnmua a anum¶rt; uu amm ¶rt;ua uuu.

     

Accuracy assessments of recent earth gravity models using crossover altimetry

Summary The calibrated variance-covariance matrices of the harmonic geopotential coefficients of the recent combined model JGM 2 has been tested and verified by independent crossover altimetry from TOPEX/Poseidon and ERS 1 using the Latitude Lumped Coefficients in the southern oceans area. Although orbits are not yet available for these missions with other recent models for which error matrices have been released, by comparison with JGM 2 results and field differences we also confirm that the error matrices for the satellite model GRIM 4S4p and the combined data model JGM 3 are also generally valid. Projections of these matrices for a variety of inclinations show that many unused orbits of even moderate altitude (≈ 800 km) will still yield trajectory crossover errors at a level of many tens of centimeters even with the latest orbitgeopotential models.     

Equation of radiation balance of the earth

Summary The equation of the planetary radiation balance of the Earth is derived and discussed. The changes of the temperature of the Earth due to the change in the cloud cover, the cloud albedo and the Earth's surface albedo are analysed in detail.     

ELF and VLF electric field measurements with the Interkosmos 10 satellite

Summary The ELF-VLF experiment onboard the Interkosmos 10 satellite consisted mainly of a broadband receiver covering the frequency range from 20 Hz to 22 kHz. The signal level in this broad band has also been measured, as well as the level in two narrow bands with centre frequencies of 720 Hz and 4 kHz. The electric component of the ELF-VLF fields has been measured by using an electric dipole antenna, 2.35 m in length. The purpose of this paper is to characterise the data obtained by the broadband RTT transmissions at the Panská Ves station during the seven-months active period of the satellite. The spectral analysis of all broad-band ELF-VLF recordings has been used. Examples of some typical phenomena, most frequently observed at different invariant latitudes are given.